ABSTRACT Advances in modern dental materials provide patients and practitioners a number of choices from which to create more pleasing and natural-looking restorations. So we should learn the characteristics of each tooth-colored materials and to base their judgment of which type to use on in-depth consideration of the many products available.

KEYWORDS : Nanotechnology , Nanocomposite , Dentistry, Composite

Definition: Nanotechnology is the design, fabrication, characterisation and utilization of materials, structures and devices, which are less than one hundred nanometres in at least one dimension” 'Nano-technology' is the production technology to get the extra high accuracy and ultra fine dimensions, i.e. the preciseness and fineness on the order of 1 nm (nanometer), 10(superscript)-9 meter in length. The name of 'Nano-technology' originates from this nanometer.

• Nanocomposites are a recent development on the market. They contain filler particles with sizes less than 10 nm (0.01 µm) and are claimed to provide increased aesthetics, strength and durability

Nanoparticles • Two types1.Nanomeric (NM) - Monodisperse nonaggregated and nonagglomerated silica nanoparticles.2. Nanoclusters (NC)- It is formed by partially fusing or sintering some of these nanometer-sized particles.

Nanosize silica particles are 20-75nm in diameter.

• The silica particles are treated with 3-methacryloxypropyltrimethoxysilane,(MPTS) using proprietary method. • MPTS is a bifunctional coupling agent, contains a silica ester function on one end for bonding to the inorganic surface and a methacrylate group on the other end to make the filler compatible with the resin before curing to prevent any agglomeration or aggregation. • It also allows chemical bonding of the NM filler to the resin matrix during curing. • NC fillers are of two types: 1.The first type consist of Zirconia-silica particles synthesized from a colloidal solution of silica and a Zirconly salt. The primary particle size ranges from 2-20nm, while the spheroidal agglomerated particles have a broad size distribution of 0.6um. 2. The second type are synthesized from 75nm primary particles of silica, has broad secondary particles size distribution with a 0.6 um average. The surfaces of both types of NC are treated with MPTS coupling agent to provide compatibility and chemical bonding with the organic resin. Resin matrix/system; • Bisphenol A glycidyl dimethacrylate, • Ethoxylated bisphenol A dimethacrylate, • Triethylene glycol dimethacrylate, • 1,6-bis-2,4,4-trimethylhexane.Properties: • T.S – 80- 87 Mpa. • C.S – 426- 458 Mpa. • Flexural strength – 153-177 Mpa • Fracture resistance – 1.0-1.3. • Wear – 0.01-0.04mm3. • Volumetric shrinkage – 2.0-2.09% • The commercial material is available in 3 translucent shade, 7 enamel, 13 body shades and 7 dentin shades.

Advantages: 1. Superior hardness. 2. Superior flexural strength. 3. Superior modulus of elasticity. 4. Superior translucency, excellent color density, high polish and polish retention. 5. Excellent handling property. 6. About 50% reduction in filling shrinkage. • Trade names of Nanocomposite: 1. Filtek Z350 (3M). 2. Ceram.X (Dentsply). Other uses of nanotechnology in dentistry. • Nanosolution – AdperO single Bond adhesive. • Impression material- NanoTech Elite H-D+. • Orthodontic purpose. • Implantology.Conclusion: Advances in modern dental materials provide patients and practitioners a number of choices from which to create more pleasing and natural-looking restorations. So we should learn the characteristics of each tooth-colored materials and to base their judgment of which type to use on in-depth consideration of the many products available.